Work-handling means for power-presses and like machines



June 26, 1962 H. HJRIDLEY 3,040,685

WORK-HANDLING MEANS FOR POWER-PRESSES AND LIKE MACHINES Filed Nov. 17,1958 2 Sheets-Sheet 1 June 26, 1962 H. H. RIDLEY 3,040,685

WORK-HANDLING MEANS FOR POWER-PRESSES AND LIKE MACHINES I Filed Nov. 17,1958 r 2 Sheets-Sheet 2 United States Patent 3,043 685 WORK-HANDLINGMEAIQ S FOR POWER-PRESE AND LEE MACHINES Harry Heywood Ridley, Aldridge,near Walsall, England,

This invention relates to work-handling means for power presses and likemachines and more particularly to means for unloading workpieces fromsuch machines.

According to my invention, work-handling means for power presses or likemachines comprises a rigid substantially vertical arm carryingwork-gripping means at its lower end mounted to swing about a pointintermediate its ends on a pivot guided for movement along a fixed path,a lever mounted for angular movement about a fixed point and connectedat one end to the upper end of the arm, and fluid pressure means formoving the lever angularly to cause the arm to move vertically and toswing about its pivot.

The gripping means is operated in synchronism with the movement of thearm, the arrangement for unloading or removing pressings from a powerpress being such that the gripping means is advanced to grip a pressing,the arm is raised through a small distance to lift the pressing, and thearm is then swung out to carry the pressing to a point where it isdischarged by release of the gripping means, the arm then returning toits initial position.

The work-handling means may be set in motion automatically by theclosing of a switch actuated either directly or through any convenientintermediate mechanism by a cam on the crankshaft of the press or by astriker or the like on the ram or slide, the switch being closed afterthe crankshaft has passed bottom dead centre.

A second switch is closed by a moving part of the work-handling means asthe arm approaches the upper end of its movement to release the grippingmeans and allow the arm to return. A control actuated by a part of thegripping means may be provided to stop the press if the gripping meansis not fully retracted when an appropriate point in the cycle ofoperations is reached.

Preferably the arm of the work-handling means is telescopic to allow itslength to be adjusted to suit different presses, and it carries at itslower end gripping means movable in a substantially horizontal directionand incorporating fixed and movable jaws between which the work is held.

A practical form of work-handling means in accordance with my inventionfor unloading work-pieces from a power press is illustrated by way ofexample in the accompanying drawings in which:

FIGURE 1 is a side elevation of the complete workhandling means,

FIGURE 2 is a front elevation,

FIGURE 3 is a diagram showing the path of the arm,

FIGURE 4 is a diagram of the electrical control system.

In FIGURE 1, is a rigid bracket which is adapted to be bolted orotherwise secured to the frame of a press to carry the Work-handlingmeans. The form of this bracket will depend on the design of the press.

Two spaced vertical plates 11 depending from the bracket form a rigidframe for the work-handling means and aligned slots 12 are formed in theplates. These slots are vertical throughout the major part of theirlength but a short part at the lower end is curved slightly as shown at13.

The work-handling arm 14, at a point a short distance below its upperend, carries rollers 15 working in the 3,64%,685 Patented June 26, 1962ice slots 12. The upper end of the arm is pivotally connected to thefree end of a lever 16 which is pivoted at its other end about astationary axis 17. About the middle of its length the lever has anintegral depending lug '18 to which is pivotally connected by a pin 19the free end of the piston-rod of a substantially vertical air cylinder20 mounted to rock about a fixed pivot Z1 at its upper end;

To provide the necessary rigidity the upper part of the arm 14 isconveniently bifurcated, as shown in FIG- URE 2, with parallellimbs'fitting between the plates 11, and the rollers 15' are carried onthe ends of a spindle mounted in a tube 22' extending between and weldedto the limbs of the fork. The lever 16 is also bifurcated and is pivotedon a transverse pin mounted in-bosses 23 welded to the inner faces ofthe plates 11.

The arm 14 is telescopic, the lower part being adapted to telescope intothe upper part so that the effective length of the arm can be varied tosuit different presses.

A lug 25" pivotally mounted on the lower end of the arm'14 has securedin it a substantially horizontal bar 26. A sleeve 27 fixed on the barcarries a double-acting air cylinder 28 of which the piston-rodis'adapted to advance and close a gripper assembly 29 when the cylinderis energised. The form of the gripper jaws will depend on the work to behandled.

Air under pressure is delivered through flexible hoses to the aircylinders Ztland 28 under the control of a valve or valves by which theoperation of the work-handling means is synchronised with that of thepress.

In the normal position of the arm 14- as shown in the drawings, therollers 15 lie at the lower ends of the slots 11 and the lever 16 isinclined downwardly at a small angle to the horizontal from its pivot tothe connection to the arm.

In the operation of unloading or removing pressings from the press, theair cylinder 28 'is energised to advance the gripper assembly and closeit on to: a finished pressing as soon as the tools have completed theiroperation and the moving tool has moved upwardly far enough to permitthe entry of the gripper. Then after a predetermined time delay the aircylinder 20 is energised and swings the lever 16 upwardly about itspivot 17, and the angular and upward movement imparted to the arm incombination with the curvature of the lower end of the slots 11 producesa movement of the arm such that its lower end carrying the grippingmeans is first raised substantially vertically through a small distanceand then is swung outwardly away from the press to carry the pressingoutwardly away from the tools to a point where it is released.

The path of the gripping device is shown by the lines 31, 32 in FIGURE3, the line 31 showing its path when the telescopic arm is at itsshortest length and the horizontal movement of the gripper device is atits minimum.

The line 32 shows the path when these are at their maximum. In each casethe pick-up point is indicated at 33 and it will be seen that there is ashort substantially vertical movement of the arm to lift the pressingclear of the bottom tools before the arm begins to swing out.

The dotted lines in FIGURE 1 show the limiting upper positions of thelever 16 and the arm 14. These parts may be retained in that position bya bar inserted under the lever intoa hole 34 in the plates 11 in orderto hold the arm and the gripper device out of the way for toolsetting orlike operations.

The bar 26 carrying the gripper assembly will normally be substantiallyhorizontal when the arm is in its rest position, but the angularrelationship between the bar and the arm can be adjusted to suitparticular circumstances. For this purpose a screw-threaded rod 35pivotally connected to a laterally extending arm on the lug 25 is takenthrough a hole in a bracket 36 fixed on the arm and the angular positionof the lug is adjusted by means of nuts 37 screwed on to the rod onopposite sides of the bracket. 7

The point in the outward movement of the arm at which the pressing isreleasedis conveniently controlled by a switch 40 which is verticallyadjustable on a rod 41 mounted in lugs on one of the plates 11, theswitch being tripped by the lever 16 or by the arm 14.

A convenient layout for the automatic control of the work-handlingdeviceincorporating the switch 40 is shown in FIGURE 4.

When the crankshaft of the press haspassed bottom dead-centre and thereis suflicient room for the gripper device to enter between the tools, acam 45 on the crankshaft closes a switch 46 to energise one solenoid ofa double solenoid-operated air valve 47. This admits air to the cylinder28 which advances and closes the gripper device to grip the pressing. Atthe same time air is admitted through a controllable restrictor valve toa pilot operated master valve which, after a predetermined andadjustable time delay, admits air to the cylinder 20 which raises thearm with the gripping device and pressing and swings it outwardly. Asthe arm approaches the end of its movement the switch 48 is closed andenergises the other solenoid of the valve 47 to reverse the valve. Theenergisation of the cylinder 28 is reversed so that the pressing isreleased and the gripper device is retracted, and the cylinder 20 isconnected to exhaust so that the arm returns under gravity to its restposition. A manually operated switch 48 is provided to allow thework-handling device to be operated independently of'the press.

FIGURE 4 also shows a safety switching arrangement incorporated in thepress control circuit.

A switch 49 adapted to be closed by a cam 50 on the crankshaft of thepress is' connected in parallel with a pressure-operated switch 51connected to and operated by the air pressure in the end of the cylinder28 to which air is admitted to retract the gripping means, so that ifthe supply of air under pressure to that end of the cylinder shouldfail, the switch 51 opens and the switch 49 opens and stops the press assoon as the cam 50 clears the switch.

In an alternative arrangement a limit switch is mounted on the sleeve 27and is adapted to be engaged by a striker on the moving part of thegripper assembly so that the press is stopped if the gripper has notbeen fully retracted when an appropriate point in the cycle is reached,whether the failure is due to failure of the air supply or to any othercause. e e

a It will be appreciated that work-handling means forms a complete unitwhich can readily be fitted to existing presses.

I claim:

1. Work-handling means for power presses comprising a frame, asubstantially vertical arm, a horizontal pivot member carried by the armand connected to the frame for substantially vertical movement relativethereto, work gripping means on the lower end of said farm, an actuatinglever pivoted at one end on a fixed point on the frame laterally spacedfrom the path of movement of the pivot member and pivotally connected atthe other end to the arm, and fluid pressure means operably connected tosaid lever for moving the lever angularly in a vertical plane to swingthe arm about the axis of its pivot member and move it bodily in avertical direction.

2. Work handling means for powerpresses comprising a frame, asubstantially vertical arm, a pivot membercarried by the arm,work-gripping means on the lower end of the arm, means defining a fixedvertical path in the frame in which said pivot member is guided formovement along said path, an actuating lever mounted for angularmovement in the frame about a fixed horizontal pivot laterally spaced'from the path, a pivotal connection between the lever and the upper endof said arm, and fluid-pressure means operably connected to said leverfor moving the lever angularly to cause the arm to move bodily in avertical direction and to swing about the axis of its pivot member.

a 3 Work-handling means as'in claim 2 wherein said path defining meansis a slot, said pivot member for the arm being slidably guided in saidslot in the frame, the slot being vertical except for a short curvedportion at its lower end in which the pivot lies in the normal restposition of the arm.

4. Work-handling means as in claim 2 wherein said pivot member comprisesa pin fixed transversely in the arm a short distance from its upper end,rollers on said at an intermediate point in its length.

6. Work-handling means as in claim 2 wherein the dispositions of thearm, the actuating lever, and the path in which the pivot member of thearm is guided, are such that on energisation of the fluid pressure meansthe arm is first raised bodily through a small distance to lift awork-piece held in the gripping means clear of the tools of a press towhich the work handling means is fitted and then-the arm is rockedangularly to carry the workpiece outwardly away from the tools to apoint where i it is released.

7. Work-handling meansas in claim 2 wherein said work gripping means onthe lower end of the arm comprises a gripping device slidably mounted onthe arm 7 for movement thereon in a substantially horizontal directionand a double-acting fluid pressure motor adapted when energised in onedirection to advance the gripping device into engagement with and closeit on to a workpiece and when energised in the other direction torelease the work-piece and retract the gripping device.

8. Work-handling means for a power press operating cyclically comprisinga frame secured to the press, a substantially vertical arm, a horizontalpivot member carried by the arm and connected to the frame forsubstantially vertical movement relative thereto, work-gripping means onthe lower end of said arm, an actuating lever pivoted at one end on afixed point on the frame and pivotally connected to the arm, fluidpressure operating means operably connected to said lever for moving thelever angularly in a vertical plane to swing the arm about its pivot andmove it bodily in a vertical direction, and a control means forenergizing said fluid pressure means actuated by a moving part of thepress during each cycle thereof to initiate an operative stroke of saidarm in synchronism with the operation of the press.

9. Work-handling means as in claim 8 further comprising double actingfluid pressure means connected for actuating said work gripping means, asolenoid-operated valve means operable to energize said double-actingfluid pressure means in one direction to grip a work piece andsubsequently, after a predetermined time interval, energize the fluidpressure means for moving the arm, said control means including a firstswitch actuated by a moving part of the press for controlling said valveto cause the gripping of a work-piece and the movement of the arm on anoperative stroke of the press, and a second switch actuated by the armfor reversing the valve to cause the release of the work-piece and theretu-rn of the arm.

10. Work-handling means as defined in claim 8 further comprising presscontrol means including means for-stopping the press upon failure ofsaid double acting fluid pressure means, and means for rendering saidlast men- =tioned means operative at a predetermined point in the i 1cycle of press operation.

11. Work-handling means for a power press or the like comprising an armof substantial length having work gripping means at one end, a frame,mounting means for pivotally mounting the arm on the frame for swingingmovement about a first pivotal axis extending transversely of the lengthof said arm, said mounting means permitting also movement of said firstpivotal axis along a predetermined path, a lever pivoted to said arm ona second pivotal aXis' parallel to said first pivotal axis but spacedtherefrom, means engaging said lever at point spaced from said secondpivotal axis for guiding the path of movement of the lever, and fluidpressure means connected to the lever to move it along its path ofmovement and thereby to move said arm.

6 7 References Cited in the file of this patent UNITED STATES PATENTS796,541 Tompkins Aug. 8, 1905 1,597,967 Grant et al. Aug. 31, 19261,859,956 Canfield May 24, 1932 2,275,561 'Sahlin Mar. 10, 19422,609,776 Sahlin Sept. 9, 1952 2,763,167 Sahlin Sept. 18, 1956 2,781,136Sehn et a1 Feb. 12, 1957 2,811,266 Udal Oct. 29, 1957 2,868,582 LoisellJan. 13, 1959 OTHER REFERENCES Sahlin Iron Hand Unloading Machines,Sahlin Engineering Co., PO. Box 289, Birmingham, Michigan, pp. Sand 8. v

